Look for Polymetal/Alumapanel/Grimco MaxMetal or equivalent. It would be 3mm of thermoplastic with aluminum skins and a baked enamel finish on both sides. (with some 6mm, one-sided options). Stiffness equals 5/8" plywood. One use is commercial signage, so sign shops become a source of cut-offs.
The samples shown were sheared, rolled and braked on hand tool with an 18" (0.5m ?) lever arm. I think a pneumatic nibbler would be an ideal cut-out tool.
The enameled finish saves a lot of work compared to e.g., fiberglass.